title: Should modest elevations in prostate-specific antigen, International Prostate Symptom Score, or their rates of increase over time be used as surrogate measures of incident benign prostatic hyperplasia?
abstract: Although surrogate measures of benign prostatic hyperplasia (BPH) are often used in epidemiologic studies, their performance characteristics are unknown. Using data from the Prostate Cancer Prevention Trial (n = 5,986), we evaluated prostate-specific antigen (PSA), International Prostate Symptom Score (IPSS), and their rates of change as predictors of incident BPH. BPH (n = 842 cases) was defined as medical or surgical treatment or at least 2 IPSS of 15 or higher. Proportional hazards models were used to measure the associations of baseline PSA, IPSS, and their velocities over 2 years with BPH risk, and time-dependent receiver-operating characteristic curves were used to measure their discriminatory performance. Unit increases in PSA, IPSS, and IPSS velocity were associated with 34%, 35%, and 29% (all P < 0.001) increases in BPH risk, respectively. The areas under the receiver-operating characteristic curves were significantly greater than 0.5 for PSA (0.58, 95% confidence interval (CI): 0.56, 0.60), IPSS (0.77, 95% CI: 0.75, 0.78), and IPSS velocity (0.63, 95% CI: 0.61, 0.65); however there were no cut points at which sensitivity and specificity were both above 75%. We concluded that moderate elevations in PSA, IPSS, or their rates of change should not be used as surrogate measures of incident BPH.
authors.affiliation: Fred Hutchinson Cancer Research Center, Cancer Prevention Program, Seattle, WA 98109-1024, USA. jschenk@fhcrc.org
authors.forename: Jeannette M
authors.initials: JM
authors.lastname: Schenk
authors.forename: Rachel
authors.initials: R
authors.lastname: Hunter-Merrill
authors.forename: Yingye
authors.initials: Y
authors.lastname: Zheng
authors.forename: Ruth
authors.initials: R
authors.lastname: Etzioni
authors.forename: Roman
authors.initials: R
authors.lastname: Gulati
authors.forename: Catherine
authors.initials: C
authors.lastname: Tangen
authors.forename: Ian M
authors.initials: IM
authors.lastname: Thompson
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kristal
mesh_terms: D000368:Aged; D015415:Biomarkers; D015992:Body Mass Index; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood*; D012372:ROC Curve; D044469:Racial Groups; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D017430:Prostate-Specific Antigen
keywords: International Prostate Symptom Score; benign prostatic hyperplasia; prostate-specific antigen